I-90 - Snoqualmie Pass East - Stampede Pass Interchange to Cabin Creek Interchange (Phase 4)

Project news

Why is WSDOT improving safety and reliability on I-90?

Phase 4 is part of a 15-mile corridor improvement project to improve safety and reliability and reduce congestion along I-90 from Hyak to the Easton vicinity. 

On an average day, 28,000 vehicles travel over Snoqualmie Pass and traffic numbers double on weekends and holidays. Traffic volumes are expected to increase 2.1 percent every year, reaching an average of over 41,000 vehicles per day by 2030.

This phase includes two miles of improvements between the Stampede Pass Interchange to the Cabin Creek Interchange.  

The end result

WSDOT will continue to increase capacity and improve safety by:

  • Adding a new lane in each direction
  • Replacing concrete pavement
  • Stabilizing rock slopes
  • Building wildlife crossings
  • Straightening the roadway 
  • Adding new chain-up area

Needs & benefits

  • Safety. WSDOT will improve the driving surface on I-90 by replacing the concrete pavement, straightening the roadway, and adding truck climbing lanes.
  • Congestion Relief. WSDOT will increase capacity by 50 percent in each direction to accommodate projected traffic volumes for the next 20 years by adding a lane in each direction.
  • Environmental. WSDOT will minimize impacts to the environment and improve movement of wildlife.


Summer 2026 - construction begins
Fall 2029 - scheduled completion


Financial Data for PIN 509094A
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $0
Pre-Existing Funds (PEF) $0
CWA $206,345
Total $206,345


Andrew Byrd
Project Engineer

Meagan Lott

Thumbnail - I-90 - Phase 3 and 4 map